1. Field of the Invention
The invention generally relates to machines for finishing concrete slabs, and more particularly to a method and machine for mechanically finishing dished-shaped concrete slabs of inverted conical configurations having particular utility as foundations for wine tanks and the like.
2. Description of the Prior Art
As can readily be appreciated by those familiar with the art of finishing concrete, substantial time and effort must be devoted to achieving proper slopes, grades and shapes in those instances where such factors are of significance. For example, in the erection of tanks, such as wine tanks and the like, concrete foundations, or bases for the tanks, normally are of an inverted, conical configuration. That is to say, each foundation normally comprises a concave, dished-shaped slab having an annular periphery disposed in a horizontal plane and a center spaced vertically downwardly from the plane of the periphery of the slab. In order to impart the desired shape and slope to the slab, substantial effort heretofore has been required during the finishing of the slab.
As a consequence of the level of skill and the effort usually required in properly shaping slabs employed as foundations for wine tanks and the like, there exists a need for a mechanized trowel, or machine, having a capability of finishing concrete slabs in an economic and facile manner such that desired finishes, shapes, and grades become readily achievable at reduced costs.
During the course of a preliminary search conducted for the invention hereinafter more fully described and claimed, the following patents were discovered:
U.S. Pat. No. 1,731,231; Chenoweth; Oct. 8, 1929 PA1 U.S. Pat. No. 3,229,827; Kucera; Jan. 18, 1966 PA1 U.S. Pat. No. 3,270,634; Borges; Sept. 6, 1966 PA1 U.S. Pat. No. 3,450,011; Godbersen; June 17, 1969 PA1 U.S. Pat. No. 4,132,450; Hansen; Jan. 2, 1979 PA1 U.S. Pat. No. 4,142,815; Mitchell; Mar. 6, 1979
It is noted that the patent to Chenoweth U.S. Pat. No. 1,731,231 discloses a machine for spreading aggregate or plastic material on surfaces such as roadway surfaces; the patent to Godbersen, U.S. Pat. No. 3,450,011 provides a concrete finishing machine utilizing a traveling carriage for transporting a finishing member transversely over a slab; the patents to Kucera U.S. Pat. No. 3,229,827 and Hansen U.S. Pat. No. 4,132,450, disclose material-handling apparatuses for use in unloading silos; while the patents to Borges and Mitchell were selected simply as being of further interest.
In summary, it is noted that the use of augers for spreading cement is known and also it is known to employ a pivotal auger in handling silage. However, it is believed to be apparent that none of the patents discovered during the course of the search contain a suggestion for a mechanized trowel particularly adapted for finishing concrete slabs of dished-shaped configurations, or that any of the structures disclosed in any of the patents discovered in the search could be so employed.
It is, therefore, the general purpose of the instant invention to provide a machine and method for finishing concrete slabs of circular dished-shaped configurations.